There is an argument that the whole of Debian belongs in 'contrib' rahter
than 'main' because there is no entirely free (as in speech) machine on
which it can run.

I think there are free CPU designs around and you could probably
compile a free emulator to run on one of them.

FYI, you don't even need an emulator to get a free CPU. There is an
implementation of the Sparc v8 processor called Leon-2, licensed under
GNU LGPL. The project was initially started by the European Space
Agency. The VHDL code is available, so you just need an FPGA.